I understand that this is pure speculation but with the most recent update/news article giving us information about relevant Light Level drops bungie ended their article stating "There are more changes to come. Those announcements are yet to be... unmasked."
I understand that the use of the word unmasked could simply mean that there are new things coming that we don't know of but it made me think. With how they love to tease at things this could possibly have to do with:
1. Festival of the Lost (masks for us to wear)
2. Efrideet being unmasked
3. The Speaker being unmasked
4. Eris Morn being unmasked
5. All masked guarians having them temporarily removed for our amusement.
Those were my initial thoughts. Of course the most plausible would be #1 but I still thought this was an interesting choice of words.